# FeatureSummary

Functions for generating a summary of enabled/disabled features.

These functions can be used to generate a summary of enabled and disabled packages and/or feature for a build tree such as:

    -- The following OPTIONAL packages have been found:
    LibXml2 (required version >= 2.4), XML processing lib, <http://xmlsoft.org>
       * Enables HTML-import in MyWordProcessor
       * Enables odt-export in MyWordProcessor
    PNG, A PNG image library., <http://www.libpng.org/pub/png/>
       * Enables saving screenshots
    -- The following OPTIONAL packages have not been found:
    Lua51, The Lua scripting language., <http://www.lua.org>
       * Enables macros in MyWordProcessor
    Foo, Foo provides cool stuff.

## Global Properties

`FeatureSummary_PKG_TYPES`

The global property `FeatureSummary_PKG_TYPES` defines the type of packages used by FeatureSummary.

The order in this list is important, the first package type in the list is the least important, the last is the most important. the of a package can only be changed to higher types.

The default package types are , `RUNTIME`, `OPTIONAL`, `RECOMMENDED` and `REQUIRED`, and their importance is `RUNTIME < OPTIONAL < RECOMMENDED < REQUIRED`.

`FeatureSummary_REQUIRED_PKG_TYPES`

The global property `FeatureSummary_REQUIRED_PKG_TYPES` defines which package types are required.

If one or more package in this categories has not been found, CMake will abort when calling `feature_summary()` with the ‘FATAL_ON_MISSING_REQUIRED_PACKAGES’ option enabled.

The default value for this global property is `REQUIRED`.

`FeatureSummary_DEFAULT_PKG_TYPE`

The global property `FeatureSummary_DEFAULT_PKG_TYPE` defines which package type is the default one. When calling `feature_summary()`, if the user did not set the package type explicitly, the package will be assigned to this category.

This value must be one of the types defined in the `FeatureSummary_PKG_TYPES` global property unless the package type is set for all the packages.

The default value for this global property is `OPTIONAL`.

`FeatureSummary_<TYPE>_DESCRIPTION`

The global property `FeatureSummary_<TYPE>_DESCRIPTION` can be defined for each type to replace the type name with the specified string whenever the package type is used in an output string.

If not set, the string “`<TYPE>` packages” is used.

## Functions

`feature_summary`

      feature_summary( [FILENAME <file>]
                       [APPEND]
                       [VAR <variable_name>]
                       [INCLUDE_QUIET_PACKAGES]
                       [FATAL_ON_MISSING_REQUIRED_PACKAGES]
                       [DESCRIPTION "<description>" | DEFAULT_DESCRIPTION]
                       [QUIET_ON_EMPTY]
                       WHAT (ALL
                            | PACKAGES_FOUND | PACKAGES_NOT_FOUND
                            | <TYPE>_PACKAGES_FOUND | <TYPE>_PACKAGES_NOT_FOUND
                            | ENABLED_FEATURES | DISABLED_FEATURES)
                     )

  The `feature_summary()` macro can be used to print information about enabled or disabled packages or features of a project. By default, only the names of the features/packages will be printed and their required version when one was specified. Use `set_package_properties()` to add more useful information, like e.g. a download URL for the respective package or their purpose in the project.

  The `WHAT` option is the only mandatory option. Here you specify what information will be printed:

  `ALL`
    print everything
  `ENABLED_FEATURES`
    the list of all features which are enabled
  `DISABLED_FEATURES`
    the list of all features which are disabled
  `PACKAGES_FOUND`
    the list of all packages which have been found
  `PACKAGES_NOT_FOUND`
    the list of all packages which have not been found

  For each package type `<TYPE>` defined by the `FeatureSummary_PKG_TYPES` global property, the following information can also be used:

  `<TYPE>_PACKAGES_FOUND`
    only those packages which have been found which have the type <TYPE>
  `<TYPE>_PACKAGES_NOT_FOUND`
    only those packages which have not been found which have the type <TYPE>

  With the exception of the `ALL` value, these values can be combined in order to customize the output. For example:

      feature_summary(WHAT ENABLED_FEATURES DISABLED_FEATURES)

  If a `FILENAME` is given, the information is printed into this file. If `APPEND` is used, it is appended to this file, otherwise the file is overwritten if it already existed. If the VAR option is used, the information is “printed” into the specified variable. If `FILENAME` is not used, the information is printed to the terminal. Using the `DESCRIPTION` option a description or headline can be set which will be printed above the actual content. If only one type of package was requested, no title is printed, unless it is explicitly set using either `DESCRIPTION` to use a custom string, or `DEFAULT_DESCRIPTION` to use a default title for the requested type. If `INCLUDE_QUIET_PACKAGES` is given, packages which have been searched with `find_package(... QUIET)` will also be listed. By default they are skipped. If `FATAL_ON_MISSING_REQUIRED_PACKAGES` is given, CMake will abort if a package which is marked as one of the package types listed in the `FeatureSummary_REQUIRED_PKG_TYPES` global property has not been found. The default value for the `FeatureSummary_REQUIRED_PKG_TYPES` global property is `REQUIRED`.

  The `FeatureSummary_DEFAULT_PKG_TYPE` global property can be modified to change the default package type assigned when not explicitly assigned by the user.

  If the `QUIET_ON_EMPTY` option is used, if only one type of package was requested, and no packages belonging to that category were found, then no output (including the `DESCRIPTION`) is printed or added to the `VAR` variable.

  Example 1, append everything to a file:

      include(FeatureSummary)
      feature_summary(WHAT ALL
                      FILENAME ${CMAKE_BINARY_DIR}/all.log APPEND)

  Example 2, print the enabled features into the variable enabledFeaturesText, including QUIET packages:

      include(FeatureSummary)
      feature_summary(WHAT ENABLED_FEATURES
                      INCLUDE_QUIET_PACKAGES
                      DESCRIPTION "Enabled Features:"
                      VAR enabledFeaturesText)
      message(STATUS "${enabledFeaturesText}")

  Example 3, change default package types and print only the categories that are not empty:

      include(FeatureSummary)
      set_property(GLOBAL APPEND PROPERTY FeatureSummary_PKG_TYPES BUILD)
      find_package(FOO)
      set_package_properties(FOO PROPERTIES TYPE BUILD)
      feature_summary(WHAT BUILD_PACKAGES_FOUND
                      Description "Build tools found:"
                      QUIET_ON_EMPTY)
      feature_summary(WHAT BUILD_PACKAGES_NOT_FOUND
                      Description "Build tools not found:"
                      QUIET_ON_EMPTY)

`set_package_properties`

      set_package_properties(<name> PROPERTIES
                             [ URL <url> ]
                             [ DESCRIPTION <description> ]
                             [ TYPE (RUNTIME|OPTIONAL|RECOMMENDED|REQUIRED) ]
                             [ PURPOSE <purpose> ]
                            )

  Use this macro to set up information about the named package, which can then be displayed via FEATURE_SUMMARY(). This can be done either directly in the Find-module or in the project which uses the module after the find_package() call. The features for which information can be set are added automatically by the find_package() command.

  `URL <url>`
    This should be the homepage of the package, or something similar. Ideally this is set already directly in the Find-module.
  `DESCRIPTION <description>`
    A short description what that package is, at most one sentence. Ideally this is set already directly in the Find-module.
  `TYPE <type>`
    What type of dependency has the using project on that package. Default is `OPTIONAL`. In this case it is a package which can be used by the project when available at buildtime, but it also work without. `RECOMMENDED` is similar to `OPTIONAL`, i.e. the project will build if the package is not present, but the functionality of the resulting binaries will be severely limited. If a `REQUIRED` package is not available at buildtime, the project may not even build. This can be combined with the `FATAL_ON_MISSING_REQUIRED_PACKAGES` argument for `feature_summary()`. Last, a `RUNTIME` package is a package which is actually not used at all during the build, but which is required for actually running the resulting binaries. So if such a package is missing, the project can still be built, but it may not work later on. If `set_package_properties()` is called multiple times for the same package with different TYPEs, the `TYPE` is only changed to higher TYPEs (`RUNTIME < OPTIONAL < RECOMMENDED < REQUIRED`), lower TYPEs are ignored. The `TYPE` property is project-specific, so it cannot be set by the Find-module, but must be set in the project. Type accepted can be changed by setting the `FeatureSummary_PKG_TYPES` global property.
  `PURPOSE <purpose>`
    This describes which features this package enables in the project, i.e. it tells the user what functionality he gets in the resulting binaries. If set_package_properties() is called multiple times for a package, all PURPOSE properties are appended to a list of purposes of the package in the project. As the TYPE property, also the PURPOSE property is project-specific, so it cannot be set by the Find-module, but must be set in the project.

  Example for setting the info for a package:

      find_package(LibXml2)
      set_package_properties(LibXml2 PROPERTIES
                             DESCRIPTION "A XML processing library."
                             URL "http://xmlsoft.org/")
      # or
      set_package_properties(LibXml2 PROPERTIES
                             TYPE RECOMMENDED
                             PURPOSE "Enables HTML-import in MyWordProcessor")
      # or
      set_package_properties(LibXml2 PROPERTIES
                             TYPE OPTIONAL
                             PURPOSE "Enables odt-export in MyWordProcessor")

      find_package(DBUS)
      set_package_properties(DBUS PROPERTIES
        TYPE RUNTIME
        PURPOSE "Necessary to disable the screensaver during a presentation")

`add_feature_info`

      add_feature_info(<name> <enabled> <description>)

  Use this macro to add information about a feature with the given `<name>`. `<enabled>` contains whether this feature is enabled or not. It can be a variable or a list of conditions. `<description>` is a text describing the feature. The information can be displayed using `feature_summary()` for `ENABLED_FEATURES` and `DISABLED_FEATURES` respectively.

  Example for setting the info for a feature:

      option(WITH_FOO "Help for foo" ON)
      add_feature_info(Foo WITH_FOO "The Foo feature provides very cool stuff.")

## Legacy Macros

The following macros are provided for compatibility with previous CMake versions:

`set_package_info`

      set_package_info(<name> <description> [ <url> [<purpose>] ])

  Use this macro to set up information about the named package, which can then be displayed via `feature_summary()`. This can be done either directly in the Find-module or in the project which uses the module after the `find_package()` call. The features for which information can be set are added automatically by the `find_package()` command.

`set_feature_info`

      set_feature_info(<name> <description> [<url>])

  Does the same as:

      set_package_info(<name> <description> <url>)

`print_enabled_features`

      print_enabled_features()

  Does the same as

      feature_summary(WHAT ENABLED_FEATURES DESCRIPTION "Enabled features:")

`print_disabled_features`

      print_disabled_features()

  Does the same as

      feature_summary(WHAT DISABLED_FEATURES DESCRIPTION "Disabled features:")